In mid-May of 2015, a broadcast announced that hundreds of saiga antelopes suddenly died in the Kostanay region of Kazakhstan. Soon after, a wave of similar occurrences were reported all across central Kazakhstan. Fatalities promptly rose from hundreds to thousands, then to tens of thousands, and finally to over a hundred thousand animals. More than 140,000 saigas, about half of the world’s remaining population, mysteriously died over the span of a few days. Researchers are flummoxed by the mysterious cause of death; although it’s almost certainly viral.
Scientists expect that pasteurellosis, a digestive illness, may be the cause of this epizootic. But the presence of this bacteria in the saigas intestinal tract is natural, so it is unknown what ignited the collapse of their immune systems. Whatever the cause, the result an affliction that has 100% mortality rate for the males, females and calves. It begins with sluggishness and disorientation. The affected animals froth at the mouth and suffer from diarrhea. A few hours later, they become unable to stand and breathe properly. Death soon follows.
In recent decades, saigas have experienced quite a few outbreaks that have resulted in large-scale mortality. They seem to always be just on the verge of extinction. For example, in the 1980s, two thirds of the global population of saigas perished. And as recently as 2010, a third of them were lost. What could possibly be the reason for these almost periodic devastations?
In the past, these strange-looking creatures inhabited lands that stretched from Alaska to as far west as the United Kingdom. Unlike most of the Pleistocene megafauna (the animals we often associate as mammoths and mastodons and saber-tooth cats) that died out due to overhunting by humans, prehistoric saigas were also over-hunted and driven to live in the remote steppe grasslands and semi-arid deserts of central Asia.
Despite losing their prehistoric habitats, saigas have become well adapted to their harsh environment which is prone to many dust storms, little to no annual rainfall, and volatile temperatures. They now play a major role in the ecosystem they inhabit. They recycle nutrients through their grazing. They prevent wildfires because they lower the over abundance of brush. They also serve as a vital food source for predators; having once even fed poor, rural inhabitants after the collapse of the Soviet Union
Unfortunately, forcing this once global species to exclusive areas has made them severely homogeneous and especially susceptible to disease. It certainly doesn’t help that a majority of births result in twins. Their condition is similar to the dangers of monoculture. Monocultures are a single type of plant growing in large areas. These conditions make monocultures very vulnerable. One monocrop can be wiped out completely by a single virus, fungus, destructive insect, or other disease. A farmer could lose his entire crop, his entire livelihood, to one microbe. Monoculturalism, while producing enormous amounts of food, only encourages more disease, weeds, and destructive insects. These pests build resistance and easily thrive under the unchanging nature of a monoculture. Seasonally, thousands of saigas migrate during the winter to warmer climates. In the springtime, the mothers universally give birth; they often all give birth as close as within a few days of each other. This unchanging pattern is the perfect conditions for a disease to thrive. Recall the arrival of the boll weevil in the United States in 1892. A single species of insect decimated the poor, cotton-dependent regions of the United States. The effect was so great that it forced a revolution in southern economics.
Likewise the Saiga face a very similar threat in the form of an unknown pathogen. This is unfortunate, as the herd has recovered significantly since the 1990s. The fall of the Soviet Union in 1991 nearly pushed the saigas to extinction. The collapse of government spiked rural poverty and eliminated the means of protecting the saiga. This resulted in an explosion of hunting and poaching, almost 95% of the population was destroyed. Saigas provided easy meals and their horns became highly valued in Asian medicine (This actually led to the saigas’ extermination in China during the 1960s). Their condition mirrors the historical devastation of our own American bison. The North American species of bison once roamed the grasslands of North America in massive herds. The buffalo began to disappear as they were hunted for food by railroad workers and relocated Indians. Now they reside only in pockets of their once expansive territory.
Perhaps the exact cause of the saiga massive deaths will soon be discovered. But whatever the cause, it is all too apparent that without diversity, an environment is unsustainable.
Scientific information and data:
Ted Steinberg, Down to Earth: Nature’s Role in American History, 3rd edition (New York: Oxford University Press, 2013): chapter 7.